[gillonnet]

hi, do empty silencer(just pipe) effect  UCE EFI Engine performance?

thanks

[prof_stack]

Yes it will.  Less low end power, more high-end (as it were) power, and a louder report that will get everyone's attention (usually not in a good way). 

Removing the cat will also put more crap into the air.

On its own, the EFI computer cannot handle the change properly.

[GlennF]

... and lets not forget fuel consumption of a ferguson tractor.

Fitting 1 3/4 " Harley drag pipe torque cones in the headers will offset some of the negative effects by blocking pulses bouncing back up the open pipes - but you still have the problem of no back pressure.  Open pipes are mainly for looks and generally are used for show bikes and bobbers only.

[Sub]

This is my experience too.. way too loud. This bike needs some dampening and back pressure to run well. The EFI pipe is a good choice.

[BRADEY]

They are bad for your bike......